Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

053
FXUS63 KLOT 181813
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
113 PM CDT Wed Mar 18 2026

.KEY MESSAGES...

- Another clipper system may deliver rain showers tonight
  (Wednesday night) into Thursday morning.

- Temperatures will warm toward the 60s to locally lower 70s
  Friday and Saturday. A cold front passage Saturday night into
  Sunday will bring a sharp cool down, especially near the lake.

&&

.DISCUSSION...
Issued at 113 PM CDT Wed Mar 18 2026

Another weak clipper system will move southeast across the
region late tonight into Thursday morning bringing a chance of
rain showers. Much of the guidance is trending drier with really
only the HRRR showing several hours of showers moving through
the area around and after daybreak Thursday morning. Quite a bit
of dry air in the low levels that any precipitation would have
to overcome and given these trends have lowered pops some and
also adjusted timing later with pops continuing across northwest
IN through late Thursday morning. Temps will likely drop into
the lower 30s, possibly upper 20s over the deeper snowpack
areas, this evening and then slowly rise through the overnight
hours. However, confidence is low for temp trends tonight into
Thursday morning and if rain showers do develop, there will be a
low chance for freezing rain and this will need to be monitored
later this evening into the overnight hours. Currently, do not
have any freezing rain mention during this time period.

Temps begin to warm into the 50s for most of the area Thursday,
though easterly winds will keep the lakeshore areas and far
northeast IL cooler. A lake breeze may move inland Thursday
afternoon, spreading the cooler air further inland.

Southwest winds on Friday will allow warmer temps all the way to
the lakeshore with 60s across northern IL and lower 70s across
central IL. A cold front is expected to move south across the
area Friday afternoon into Friday evening with uncertainty for
timing. When it does, there will be a large temperature drop for
the lakeshore areas. Winds shift back around to the southwest on
Saturday with highs back into the upper 60s/lower 70s for much
of the area.

Another stronger cold front is expected to move across the area
on Sunday and there remains quite a bit of uncertainty for its
timing/location. There seems to be a slowly increasing consensus
for the cold front to be moving through the local area Sunday
morning, which would allow for much cooler temps (40s) across
the northern cwa/lake shore and then quite warm temps (60s/70s)
across the south. Only change to the blended grids was to lower
temps for the lakeshore areas given the increasing chances for
onshore winds for much of Sunday. There is also a low chance for
a few showers with this front on Sunday. Dry weather is
expected early next week. cms

&&

.AVIATION /18Z TAFS THROUGH 00Z FRIDAY/...
Issued at 1223 PM CDT Wed Mar 18 2026

Main Items of Note:

- Gusty south-southwest winds this afternoon

- Potential for a period of rain showers Thursday morning,
  possibly followed by a period of MVFR CIGs

South-southwest winds gusting up to 20-25 kt at the start of the
period over the Chicago metro will veer to 220-250 deg by late
afternoon and diminish. Winds will then become light/VRB to calm
overnight into Thursday morning, and likely east to southeast
with time into Thursday afternoon (favoring east near the lake
due to lake influence).

A moisture starved disturbance may bring a period of rain
showers (PROB30s in Chicago metro TAFs) Thursday morning,
ending by the mid to late morning if it occurs. Held onto
temporary lower MVFR CIGs after the possible rain moves out,
through early Thursday afternoon.

Castro

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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